ISBLANK(3P)

💖 ISBLANK(3P) — bestie's guide to the blank character check 💖

okay so real talk: this is a page from the POSIX Programmer's Manual. welcome to the group chat, pull up a chair 🫶

🌸 PROLOG

so like, heads up before we even start: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ — so bestie, if you're on Linux, go consult the corresponding Linux manual page for the deets on Linux behavior. OR. Plot twist. The interface might not even be implemented on Linux at all. 🙈 It's giving "check before you commit."

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✨ NAME

isblank, isblank_l — test for a blank character 💅

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🎀 SYNOPSIS

#include <ctype.h>

int isblank(int c);
int isblank_l(int c, locale_t locale);

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🦋 DESCRIPTION

okay so for isblank(): the functionality described on this reference page is aligned with the ISO C standard. If there's any conflict between what's written here and the ISO C standard, that conflict is unintentional — no drama intended, fr fr. This volume of POSIX.1‐2017 defers to the ISO C standard. periodt.

The isblank() and isblank_l() functions shall test whether c is a character of class blank in the current locale, or in the locale represented by locale, respectively. (if you wanna know what "class blank" even means, go read the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale. iykyk ✨)

The c argument is a type int, and the value of it — the application shall ensure — is a character representable as an unsigned char or equal to the value of the macro EOF. If the argument has any other value?

the behavior is undefined. 💀 not a vibe. don't do it.

And one more cautionary tale: the behavior is undefined if the locale argument to isblank_l() is the special locale object LC_GLOBAL_LOCALE, or if it is not a valid locale object handle. So like... make sure it's valid, bestie. 🫶

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👑 RETURN VALUE

The isblank() and isblank_l() functions shall return non-zero if c is a <blank>; otherwise, they shall return 0. that's it, that's the whole personality ✨

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💀 ERRORS

No errors are defined. iconic, honestly.

The following sections are informative. (yes girl, they're just vibes from here on out)

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🍓 EXAMPLES

None. 😭 nothing. empty. a blank page, if you will. (fitting.)

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🌈 APPLICATION USAGE

To ensure applications portability — especially across natural languages — only these functions and the functions in the reference pages listed in the SEE ALSO section should be used for character classification. no off-brand char classification, we stay on script 💅

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🧚 RATIONALE

None.

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⭐ FUTURE DIRECTIONS

None.

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💜 SEE ALSO

• isalnum()
• isalpha()
• iscntrl()
• isdigit()
• isgraph()
• islower()
• isprint()
• ispunct()
• isspace()
• isupper()
• isxdigit()
• setlocale()
• uselocale()

Also: the Base Definitions volume of POSIX.1‐2017, Chapter 7, Locale, <ctype.h>, <locale.h>

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📜 COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

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and that's the whole page, bestie!! 💖 this one was brought to you by IEEE/The Open Group, 2017, serving ISBLANK(3P) realness. stay blank-positive, mwah 🎀✨